Horner’s Syndrome

Synonyms of Horner’s Syndrome

Bernard-Horner Syndrome

Oculosympathetic Palsy

General Discussion

Horner syndrome is a relatively rare disorder characterized by a constricted pupil (miosis), drooping of the upper eyelid (ptosis), absence of sweating of the face (anhidrosis), and sinking of the eyeball into the bony cavity that protects the eye (enophthalmos). These are the four classic signs of the disorder.

The congenital, and more rare, form of Horner syndrome is present at birth but the cause is not known. Most often, Horner syndrome is acquired as a result of some kind of interference with the sympathetic nerves serving the eyes. The underlying causes can vary enormously, from a snake or insect bite to a neck trauma made by a blunt instrument.

Signs & Symptoms

The characteristic physical signs and symptoms associated with Horner syndrome usually affect only one side of the face (unilateral). These include drooping upper eyelid; contracted pupil; dryness (lack of sweating) on the same side of the face (ipsilateral) as the affected eye; and retraction of the eyeball.

If the onset of Horner syndrome is before two years of age, the colored portions of the eyes (irises) may be different colors (heterochromia iridis). In most cases, the iris of the affected side lacks color (hypopigmentation).

Causes

Horner syndrome may result from any one of a variety of factors, including carotid artery dissection; the development of a tumor in neck or chest cavity, particularly a neuroblastoma and a tumor of the upper part of the lung (Pancoast tumor); the development of a lesion in midbrain, brain stem, upper spinal cord, neck, or eye orbit; inflammation or growths affecting the lymph nodes of the neck; and/or surgery or other forms of trauma to the neck or upper spinal cord.

In most cases, the physical findings associated with Horner syndrome develop due to an interruption of the sympathetic nerve supply to the eye due to a lesion or growth. The lesion develops somewhere along the path from the eye to the region of the brain that controls the sympathetic nervous system (hypothalamus). The sympathetic nervous system (in conjunction with the parasympathetic nervous system) controls many of the involuntary functions of glands, organs, and other parts of the body.

Some cases of Horner syndrome occur for no other apparent reason or unknown cause (idiopathically). In other cases, some clinical researchers believe the disorder may be inherited as an autosomal dominant genetic trait.

Chromosomes, which are present in the nucleus of human cells, carry the genetic information for each individual. Human body cells normally have 46 chromosomes. Pairs of human chromosomes are numbered from 1 through 22, and the sex chromosomes are designated X and Y. Males have one X and one Y chromosome, and females have two X chromosomes. Each chromosome has a short arm designated “p” and a long arm designated “q”. Chromosomes are further sub-divided into many bands that are numbered. For example, “chromosome 11p13″ refers to band 13 on the short arm of chromosome 11. The numbered bands specify the location of the thousands of genes that are present on each chromosome.

Genetic diseases are determined by the combination of genes for a particular trait that are on the chromosomes received from the father and the mother.

All individuals carry a few abnormal genes. Parents who are close relatives (consanguineous) have a higher chance than unrelated parents to both carry the same abnormal gene, which increases the risk to have children with a recessive genetic disorder.

Dominant genetic disorders occur when only a single copy of an abnormal gene is necessary for the appearance of the disease. The abnormal gene can be inherited from either parent, or can be the result of a new mutation (gene change) in the affected individual. The risk of passing the abnormal gene from affected parent to offspring is 50% for each pregnancy regardless of the sex of the resulting child.

Affected Populations

Horner syndrome is a rare disorder that affects males and females in equal numbers and may occur at any age, among any ethnic grouping in any geographic location.

Related Disorders

Symptoms of the following disorders can be similar to those of Horner’s Syndrome. Comparisons may be useful for a differential diagnosis.

Adie Syndrome is a rare neurological disorder affecting the pupil of the eye. The symptoms of this syndrome are a large (dilated) pupil, and slow reaction to light or focus on nearby objects. In some patients the pupil may be smaller than normal rather than dilated. Absent or poor reflexes are also associated with this disorder. (For more information on this disorder, choose “Adie Syndrome” as your search term in the Rare Disease Database.)

Wallenberg Syndrome is a rare disorder caused by a blood clot. It is characterized by difficulty articulating words due to disease of the central nervous system, difficulty swallowing, a staggering gait, dizziness, low pressure of the fluid in the eyeball that gives it a round shape, lack of coordination in voluntary movement, rapid involuntary movement of the eyeball, signs of Horner’s Syndrome on the side where the lesion is present, and a loss of pain and temperature senses on the side of the body opposite the lesion.

Diagnosis

The diagnosis of Horner syndrome and the localization of the lesions that cause the disorder can be determined by pharmacological tests combined with imaging techniques such as magnetic resonance imaging and ultrasonography of the carotid artery.

Standard Therapies

Treatment

The treatment of Horner syndrome depends on the location and cause of the lesion or tumor. In some cases surgical removal of the lesion or growth may be appropriate. Radiation and chemotherapy may be beneficial to patients with malignant tumors.

Genetic counseling may be of benefit for patients and their families if they have the genetic form of this disorder. Other treatment is symptomatic and supportive.

Investigational Therapies

Information on current clinical trials is posted on the Internet at www.clinicaltrials.gov. All studies receiving U.S. government funding, and some supported by private industry, are posted on this government website.

For information about clinical trials being conducted at the National Institutes of Health (NIH) in Bethesda, MD, contact the NIH Patient Recruitment Office:

Tollfree: (800) 411-1222

TTY: (866) 411-1010

Email: prpl@cc.nih.gov

For information about clinical trials sponsored by private sources, contact:

NORD's Rare Disease Database provides brief introductions for patients and their families to more than 1,200 rare diseases. This is not a comprehensive database since there are nearly 7,000 diseases considered rare in the U.S. We add new topics as we are able to do so, with the help of rare disease medical experts.

If you are seeking information about a rare disease that is not in this database, we would suggest contacting the Genetic and Rare Diseases Information Center (GARD) at the National Institutes of Health. NIH has the most complete database of rare diseases in the U.S.

Representatives of patient organizations whose medical advisors are interested in assisting NORD in creating a report on a disease not currently covered in this database may write to orphan@rarediseases.org.